(USA Today) -- A powerful winter storm was blasting its way across the nation's midsection Thursday, with more than a foot of snow already on the ground in some areas and many more bracing for the brunt of the storm's fury.

Farther to the south, on the warmer side of the storm, eastern Texas, Louisiana and Mississippi were bracing for possible tornadoes, hail and high winds.

But snow and ice were in the mix for a wide swath of the nation. Parts of Nebraska, Oklahoma and Kansas already have been blasted with up to 13 inches of snow, the National Weather Service said Thursday. Some areas of the Midwest could see that much and more, with sleet and freezing rain exacerbating treacherous conditions.

Kelly Sugden, a weather service meteorologist in Dodge City, Kan., said the storm was moving a bit slower than was previously forecast but that it was "starting to get back together."

"It's very active," Sugden said Thursday morning, noting the snowfall was mixed with lightning and sleet showers.

Winter storm warnings and advisories have been issued from western New Mexico all the way to southwestern Virginia, a distance of more than 1,600 miles. Officials feared the storm would be the worst in the central U.S. since the Groundhog Day blizzard in 2011, which killed dozens and left hundreds of thousands powerless.

More than 176 flights had been canceled at Kansas City International Airport as of 10:30 a.m. ET, according to flight-tracking service FlightAware. Cancellations also were piling up at other airports in the storm's path, among them Dallas Fort/Worth (68 cancellations), Houston Bush Intercontinental (39), St. Louis (38), Chicago O'Hare (37), Denver (34), Omaha (22), Wichita (19), Minneapolis/St. Paul (18) and Dallas Love (14).

Some solace: Most big airlines had issued flexible rebooking policies for fliers with flights to, from or through the central United States.

Andy Foster, a weather service meteorologist in Springfield, Mo., warned that ice will continue to build on local roads, trees and power lines.

"If you have to get out at all, be really careful," he said.

In Iowa, snow is expected to fall at up to 2 inches per hour with wind gusts reaching 30 mph during the peak of the storm Thursday evening, said the weather service's Roger Vachalek.

In Oklahoma, roads were covered with a slushy mix of snow and ice that the Highway Patrol said caused a crash that killed an 18-year-old man.

In northern Arkansas, a school bus crashed Wednesday on a steep, snowy country road, leaving three students and the driver with minor injuries. Pope County Sheriff Aaron Duval said the bus slid off a road on Crow Mountain, nearly flipping before it was stopped by trees at the roadside.

The World Golf Championship Match Play event Wednesday near Tucson was suspended due to snow, and University of Nebraska officials moved a Big Ten men's basketball game against Iowa from Thursday to Saturday.

In Arkansas, an emergency preparedness drill using an ice storm as the precipitating event involving hospitals and emergency personnel in Baxter and Marion counties was canceled because of the approaching ice storm.

In California, snow stranded hundreds of drivers on mountain highways earlier on Wednesday.

The storm will also bring heavy rain, strong winds -- but also much-needed moisture -- for the drought-scorched Plains.

"Many areas of the drought region should enjoy their wettest day in months," said meteorologist Jeff Masters of the Weather Underground.

"As bad off as we are this fall and winter, it will definitely help," said climatologist Mark Svoboda.

The most recent U.S. Drought Monitor shows that 77% of the state of Nebraska is enduring "exceptional" drought conditions, the highest level of drought. In Kansas, 36% of the state is under exceptional drought.

"We'll put up with a blizzard to get this critical moisture rather than the alternative of no blizzard -- as we aren't in a position to be too choosy about how we get that moisture," Svoboda said.

Farmers in drought-plagued Kansas agreed: ""In the city you hear they don't want the snow and that sort of thing, and I am thinking, `Yes, we do,' and they don't realize that we need it," said farmer Diane McReynolds of Woodson, Kan.

"We have to have it or their food cost in the grocery store is going to go very high," she said. "We have to have this. We pray a lot for it."